Process of removing sulfur, arsenic, and other like impurities from refractory ores.



P. COTTON ARSENIG, AND OTHER LIKE IMPUBITIEB PROM PROCESS OF REMOVINGSULFUR,

RBFRADTORY OBES. APPLIUATIOH FILED APR. 20, 1907.

' Patented, May 18, 1909 wanna-ans? 1 W e '(I as (as.

Hz? Qa A) M F. GOTTON. PRGCBSS OF REMOVING SULFUR, ARSENIG, AND OTHERLIKE IMPUBITIES FROM REFRACTORY ORES. APPLIQATIGH PILEB an. 20, 1907.

922,088, Patented May 18, 1909.

2 SHEETS-SHEET II.

nfnegs c5. lnvcntor:

NMAMQ; J. a Q 4, $3M.

UNlTED STATES PATENT OFFICE.

FRANK COTTON, OF 'HORNSBY,'NEW SOUTH WALES, AUSTRALIA.

mxoon'ss or mmovnm suLmm, A'asnmc, AND-OTHER Lam mrtrnrrms momanrnaoronr onrne.

Specification of Letters Patent.

Patented May 18, 1000.

Application filed. April 20, 1007. Berla1 No. 369,881.

To all whom it may concern:

Be it known" that 1, FMNK Cor'roN, a British subject residin at Hornsby,in the Stateof New outh W ales, Commonwealth of Australia, engineer,have invented a procas .:for removing sulfur, arsenic, and other 'likeimpurities from refractory ores and preparin the same for subsequenttreatment; and a full, clear, and exact description of the same.

This invention relates to a process for preparing ores, Containing goldand silver as- 'soeiated with impurities such as sulfur, arsenic,antimony, zinc, and the like, for subsexlueut treatment for therecover-1y of the go d and silver by any process suc as coneeutrating,smelting, amalgamating, chlow rinating, cyaniding, and the inventlonconsists in eliminating the above-end other impurities so that anundesirable matte will ie prevented from forming during the subsequenttreatment of the ore for the recovery of the gold or silver.'

The process forming the subject matter of this invention involves threedistinctoperations or steps, namely :1. Combining the sulfur whenpresent in the ore with free pass oli' asia gas. 2. The subsequentoxidation by a reagent such as steam of any of the base metals presentin the desulfurized ore, ca able of oxidation. v3. Drivin oil by heat,mm the desulfnrized and oxidized ore the volatile oxide and remainingvolatile impurities. In

ores which do not contain sulfur, it may not be necessary to use thefirst step in the process i. 1/. that of reducing the ore by theaotionof hydrogen, in which case the ore is only treated as described inthe second and third steps of the recess. 'lhese operations mayconveniently. e carried out ina furnpce which I-now proceed to describeand which is illustrated in the accompanying drawn! s.

Figure l, is a perspective View 0 t, e furnace. Fig.v 2, IS alongitudinalusetstion thereof. .F1 3, 1s a vertical section, on plane3-3 1 1g. 1. F g. 4, 1s a vertical sec.-

tion on plane 4+4 Fig. 2.

Like characters of reference refer to like parts throughputthespeeification and drawm I is a furnace of which 12 is the chamber forcontaining the fuel which vis placed the furnace for t hereby declarethat the ,followingis -the 9 and of the damper 2% (iPHie chimney 26,which controlsithc draft. A certain quantity of-uir therein through thefeed door 1.1 in the side of the furnace.

6. are the fire bars and 8 is the pit of the furnace. above which arefire doors 7. a

his a damper laced on the front 10 of no purpose of regulating the airsupply and raising the temperature ot'lhe furnace when re uired.

"At the top and at rig 1t angles tothe (our bastion .chumber 12 andcommunicating therewith by n1eiiiiofpasages 23 is wharrow horizontal orechamber 21, into which A is placed the refractory ore 25 to be treated,

through feed doors .2 and 24 respectively in the top and end thereof.

522 is a partition dividing the ore chamber 21 from the combustionchamber 12.

26 is a chimney. leading from the ore chamber 21, provided with a damJet 27 which is utilized to control the'dra tand lherebV regulate thetem uu'ature of the. furnace. I

Extending through the walls of the furnace 5. just above the firedoo'rs'7, are tu'yers 13 with flaring months 14 and 15. 'lhe'mouth 15has a cover 16 with air ports 17 and a damper 1Sfor regulating the airysupply. r

19 IS a steam supply pipe leadin into the flaring mouth 15 and isprovide with a nozzle 20. The steam su ply can be controlled by anysuitable va ve placed in the steam pipe. a e 1 The fuel to be used inthe furnace is pref-' .erableslatrk coal but charcoal, coke, breezeuneven wood can be utilized.

The Intensity of combustion depends upon the quantity of air supplied tothe fuel and is therefore capable of regulation by is also drawn inthrough the air ports 17 in fthe cover l6 by the action of the steampassing from the nozzle 20. The air so drawn in ll'liXtS intimately withthe steam from the nozzleQO and maintains the combustion otthe fuel withwinch the In comes uito immediate contact. These air ports 17 arecapable of being more --or fess opened so as to adjust the uantity ofair drawn ,into the furnace for, the purpose for which it is supplied. i

Before any charge is introduced into the greater orlesser opening oi p Acharge it, to pass through furnace chamber and into the ore chamber 21furnace the latter is raised to a temperature somewhat under that towhich the ore is subsequently to be exposed during the dcsulfurizingoperation.

of ore having been previously broken into fragments about the sizeofordinar road metal is introduced into the heats ore chamber and broughtto a temperature equivalent to that of iron at a dull 10 red heat, whichtemperature is maintained sulfurizing operation 18 produced togetherwith carbon monoxid, by forcing superheated StGEI-l'l1 fl0l'll thenozzles 20 through the burnin fuel in the combustion chamber in suchlimited 'quantit as to permit of the steam being dissociatedi into itsconstituent elements 11. 0. hydrogen and oxygen by contact with theburning fuel, the oxygen combining with the carbon of the fuel to formcarbon monoxid and the hydrogen being liberated in a free state. Themixed gases thus roduced ass from the fuel over the bee ore in t e orechamber and the hydrogen acts upon the sulfur contained in the'ore andconverts it into sulfureted hydrogen which with the unafiected carbonmonoxid escapes through the chimney 26.

The pressure within the furnace is, during this and the next. operationkept slightly above atmospheric pressure by partially closing the damper27 of-th'e chimney. The time necessary to desulfurize the ore variesaccordin to the amount of sulfur present in it. be continued until theescaping gases are free from sulfu'nted hydro en. pzrssing through thewall of t e ore chem may be provided for the purpose of I50 drawing ofisamples ofgases to be'tested for sulfureted hydrogen. y

When the ore has been desulfurized as above described the sup 1y ofsteam is mciaeased so as to cause a arge pro ortion of the burning- 01'in the without undergoing: decomposition. The supsrhelted steam is carri.over the desul- 1 rized ore in the ore chamber and converts to anyreduced iron, cop r, or other oxidizable respective. ends, Y

metals present into heir removed from e desulfurizing operation shouldand the free hydrogen from the steam liberated in the operation may beallowed to escape or may be collected to be used in the earlier part ofthe )rocess.

The oxidation ta es place rapidly but the time occupied varies ofcourse'with different ores. It is easy to ascertain whether theoxidation is complete by removing samples of the ore from the orechamber and testing the same for the". presence of oxidizable metals inthe metallic state.

During the oxidizing operation a portion of the more volatile oxidsproduced will pass out throu h the chimney. After the oreasbeendesufuriz'ed and oxidized as above described the steam supply isc-ut ofi andthe air supply and draft through the furnace increased by 0 ening thedamper 9 'so as to render the com ustion more active and raise the temerature of the oreto that of iron at a brig it redheat. Any remainingvolatile impurities such as arsenic, antimony, or zinc are driven ofl'and may if it is thought desirable be recovered by condensation in acondensation chamber provided for that purpose.

After the volatile impurities have been driven oit as indicated by theabsence of white fumes escaping from the chimney the ore is removed fromthe ore chamber and allowed to cool. It is then in a comparativelyfriable and porous condition and ready for ordinary treatment bconcentrating, smeltmg, amalgamating, c lorinatmg, or cy'anid-. in

As soon as one char 'e of ore has been treated by the recess avedescribed and e ore chamber the furnace is read for the reception of afurther charge. f Havm this fully described my invention whatI c aim asnew and desire to secure by Letters Patent is: L

A- process for the preparation of aurifer ous and ,ar tifrous refractoryores contaminated 'th impurities such as sulfur, arsenic, antimony, zincand he like, consistingof the removal of-thesulfur by the action upontheheated oreof free hydrogen under shght pressure, the subsequent.oxldation of the base metals on present in the desulfuri of steam uponthe same and the ore b the action at! driving bio of oxidation,

ofi b heat from the-desulfuri-zed and 0x1- di ore of the remainingvolatile oxide resent.

In testimon whereof I-aflix my signature in presence 0 two with, i A

, FRANK COTTON.

Witnesses:

WALKER Srouonr, WILLIAM Nnw'ron.

